Oops, they did it again. Apple appears to have lost yet another iPhone 4G prototype.

Photos of the prototype have appeared on Taoviet.vn, a Vietnamese forum. There is little information about where the iPhone came from, but the individual who submitted the link to MacRumors reported that a Vietnamese businessman bought the prototype in the United States. Unlike the first prototype, the second model includes a lack of visible screws, the use of Micro-SIM cards, a new chip, and a 16GB designation. The second prototype also turns on, but appears to run on a testing software called Inferno rather than the iPhone OS.